Study of the pathogenesis of cardiac hypertrophy--biochemical differences of cultured heart cells from normotensive and spontaneously hypertensive rats.

To elucidate the metabolic properties of the heart of spontaneously hypertensive rats (SHR), we examined the uptakes of 3H-uridine (3H) and 14C-leucine (14C) into single cultured heart cells, as well as the total protein content and cell size of heart cells in the presence and absence of stimulation, and compared the findings with those obtained with Wistar Kyoto rat (WKY) cells. As a result, (1) Spontaneous uptakes of 3H and 14C into WKY heart cells increased rapidly from day 2 to days 5-6, and then decreased gradually. In contrast, in SHR heart cells a constant increase in the uptakes of 3H and 14C was observed until the 10th day. The uptakes of both 3H and 14C into 10-day-old SHR heart cells were significantly higher than those into WKY heart cells (p less than 0.05). (2) The total protein content of SHR heart cells cultured for 4 or 5 days was significantly less than that of WKY heart cells, but there was no significant difference between cells cultured for more than 6 days. As for cell size, no significant difference was observed regardless of how long the cells were cultured. However, the increment in SHR heart cell total protein and cell size during cultivation appeared to be higher than they were in WKY heart cells. (3) Stimulation of heart cells with 10(-8) - 10(-5) M L(-)-isoproterenol (ISO) for 1 hour increased the uptake of 3H into heart cells from both kinds of rats, with no significant difference between the two.(ABSTRACT TRUNCATED AT 250 WORDS)